Shot with my iPhone 5 on October 10, 2013.
I've used the following apps on this image; Leonardo, Filterstorm, Snapseed and Superimpose. Some of the processing had to be done on the phone, as my iPad 1 can't cope with large-ish images and Leonardo isn't available for iOS 5.
Here's what I started with. These were big windows, but rather high on the wall. I held the phone high overhead to try and avoid vertical lines that converged towards the top. Nearly got there.
Seeing as the windows were so tall, I decided I wanted to edit the image into one with similar dimensions.
I opened the image in Leonardo and did a rough crop at 2:3. Using the perspective tool, I tried to straighten the edges of the window. Then I cropped again (same ratio) this time, more carefully.
I've now got an image a little less than 2000 pixels tall, which is smaller than I like. When I crop an image heavily, I have found Filterstorm to be useful in re-sizing the image. I have no idea whether this is a sound technique, but what the hey. Filterstorm has a tab called "Canvas". Click that, then choose "Scale" and type in your desired new dimensions. Then click "Scale" again, which takes you back to where you can save the image.
Time to do some work on the tones, so I open the image in Snapseed.
One of the great features in Snapseed is the "selective adjustment" button. I placed an adjustment point in one of the window sections and increased the brightness (+30), the contrast (+70) and saturation (+30). You can click on the adjustment point and copy it. Then click somewhere else in the image and paste that same adjustment point. I did that in each of the six sections of the window.
I shoot for fun, with a Sony A7rIII, a Mavic Pro and my trusty iPhone 11.